Subsea electrical connectors for use underwater are known, and are for example described in the document GB 2 192 316 A. A first connector part of the subsea electrical connector has at least one pin projecting from a support which is inserted into a housing and fixed in place by a retainer ring. The pin has an axially extending conductive core, for example a copper core, which is surrounded by an insulating sleeve which is arranged to expose an area of the conductive core at or near the tip of the pin for making electrical contact with a contact socket in the second connector part of the subsea electrical connector.
In the demated condition of the first and second connector parts, the pin is exposed to the external environment and thus for example to seawater when deployed subsea. The insulating sleeve is intended to insulate the conductive core of the pin from exposure to the external environment. In the mated condition of the first and second connector parts, a portion of the pin and thus the insulating sleeve can still be exposed to surrounding seawater. Since such electrical subsea connectors can have a lifetime of more than 25 years, the insulation of the conductive core can experience long term subsea exposure. Electrophoresis may lead to an intrusion of seawater into the insulation. Furthermore, when such subsea connector is used for high voltage applications, high electrical stresses can occur in proximity to the pin of the connector, which can lead to a degradation of the material exposed to such high electrical field stresses, and may finally lead to a failure of such material, for example to the failure of a seal.
To overcome these difficulties, it is proposed in the document U.S. Pat. No. 7,794,254 B2 to make use of a metal or metalized coating formed on the outer surface of an insulating sleeve. The metal or metalized coating can suppress penetration of water into the insulating sleeve and further reduces localized condensing of equipotential electric field lines whereby electrical stresses can be reduced. Long term subsea exposure may lead to corrosion of a metal or metalized coating.
It is desirable to make subsea connectors less prone to corrosion, and to provide at the same time protection against water ingress into the electrically insulating material. Furthermore, it is desirable to reduce electrical stresses and in particular to protect components of the connector from such stresses and to avoid an electrical breakdown e.g. at insulation interfaces. Such breakdown may for example occur if the electrical field leaves the insulation material. Furthermore, it is desirable that the subsea electrical connector and its components are relatively simple and cost efficient to manufacture.